On Mon, 20 Nov 2017 12:21:52 -0800
Sami Tolvanen [off-list ref] wrote:

On Sat, Nov 18, 2017 at 01:21:39PM +1000, Nicholas Piggin wrote:

quoted

Do you have any kind of numbers for this, out of curiosity? Binary
size, performance, build time?  

I don't have performance numbers to share. Are there any specific
benchmarks you'd be interested in seeing? Build time typically
increases with LTO and in my experience, binary size tends to increase
by ~10-15% as well.

By deduction, then you must see some performance improvement? :) 

I just wonder are you doing this because there is some worthwhile
performance gain? Or to enable more testing and development of LTO?
Any clues for why a user would want to enable it.

quoted

Why is this needed? It would have been nice to get rid of the
!THIN_ARCHIVES option if you can make the patches work with the thin
archives paths.  

I believe LLVMgold doesn't know how to deal with an archive of LLVM IR
files, but I can certainly use thin archives as an index and extract
the path names for linking. I'll look into it.

Thanks, if you could. Possibly file a request with LLVMgold too, it
seems to be that toolchain support for archives is quite strong, so it
will be good to keep pushing for that.

Thanks,
Nick